WO2016019657A1

WO2016019657A1 - Method, device and storage medium for frequency offset estimate

Info

Publication number: WO2016019657A1
Application number: PCT/CN2014/092359
Authority: WO
Inventors: 魏继东; 李斌
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-08-07
Filing date: 2014-11-27
Publication date: 2016-02-11
Also published as: CN105337909B; EP3179682A1; EP3179682A4; US9900184B2; US20170214552A1; CN105337909A

Abstract

The present invention provides a method, device and storage medium for frequency offset estimate, and the method for frequency offset estimate comprises: performing initial channel estimate by receiving an Sounding Reference Signal (SRS) or a Preamble code transmitted by a User Equipment (UE) to obtain a first frequency offset estimate value of a current sub-frame of the UE (S101); determining a frequency offset range in which the first frequency offset estimate value is located, and obtaining an initial frequency offset value corresponding to the first frequency offset estimate value according to the preset correspondence between the range of the frequency offset and the initial frequency offset value (S102); determining a phase difference of adjacent pilot positions based on a received pilot sequence included in the current sub-frame, and obtaining a dual pilot frequency offset estimate value according to the phase difference within the range limited by the initial frequency offset value corresponding to the first frequency offset estimate value (S103); and acquiring a frequency offset estimate value of the current sub-frame according to the initial frequency offset value corresponding to the first frequency offset estimate value and the dual pilot frequency offset estimate value (S104).

Description

Method and device for estimating frequency offset, storage medium

Technical field

The present invention relates to communication signal processing technologies, and in particular, to a method and apparatus for frequency offset estimation, and a storage medium.

Background technique

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier transmission technology in which subcarriers are orthogonal to each other. This technique requires that subcarriers are orthogonal to each other and are very sensitive to carrier frequency offset. The carrier frequency offset problem has become one of the core issues of current OFDM technology.

At present, for the problem of solving the small frequency offset, there are many methods with high precision and simple implementation; but for the problem of large frequency offset, the accuracy of the solution is relatively low, even if some methods improve the accuracy of the frequency offset estimation, It also increases the complexity of the implementation.

Summary of the invention

In order to solve the above technical problem, embodiments of the present invention are expected to provide a method and apparatus for frequency offset estimation, and a storage medium. For the problem of large frequency offset, both frequency offset estimation accuracy and complexity of large frequency offset estimation are reduced. degree.

The technical solution of the embodiment of the present invention is implemented as follows:

In a first aspect, an embodiment of the present invention provides a method for estimating a frequency offset, and the method may include:

Performing initial channel estimation by using a received sounding reference signal (SRS, Sounding Reference Signal) or a Preamble code, and acquiring a first frequency offset estimation value of the current subframe;

Determining a frequency offset interval in which the first frequency offset estimation value is located, and according to a preset frequency offset interval Corresponding relationship between the initial frequency offset values, and acquiring an initial frequency offset value corresponding to the first frequency offset estimation value;

Determining a phase difference of adjacent pilot positions based on a pilot sequence included in the received current subframe, and acquiring a dual derivative according to the phase difference within a range defined by the initial frequency offset value corresponding to the first frequency offset estimation value Frequently biased estimate;

Obtaining a frequency offset estimation value of the current subframe according to the initial frequency offset value corresponding to the first frequency offset estimation value and the dual pilot frequency offset estimation value.

As an implementation manner, the initial channel estimation by using the received SRS or Preamble code to obtain the first frequency offset estimation value of the current subframe includes:

Acquiring channel estimation value H ^u and Y ^u receive data by receiving a current sub-frame of SRS code or the current sub-frame Preamble;

Obtaining the time domain sample value w ^u (n, ka _Rx ) of the current subframe of the receiving antenna ka _Rx according to the channel estimation value H ^u and the received data ^Yu and combined with the local pilot sequence ^Pu and the following formula:

Wherein, n represents a sampling point sequence number, u represents a user equipment UE corresponding to the current subframe, and k represents a subcarrier index corresponding to the UE,

Ka _Rx represents the receiving antenna index,

Indicates the size of a resource block (RB, Resource Block) occupied by the UE, * indicates a conjugate operation, and IDFT indicates an inverse Fourier transform;

Get current subframe ka _Rx antenna receives the phase information of the time-domain sample values w ^u (n, ka _Rx) of said receive antenna ka _Rx current frame of the first sub frequency offset estimate f ₀ ^u (ka _Rx) .

Time-domain sample values w ^u (n, ka _Rx) as an embodiment, according to the current subframe of the receiving antenna ka _Rx of the current sub-frame phase information acquisition ka _Rx antenna receiving a first frequency offset estimation The value f ₀ ^u (ka _Rx ), including:

Obtaining the phase difference between the first half and the second half of the time domain sample value w ^u (n, ka _Rx ) of the current subframe, respectively, and obtaining the phase difference between the front and back portions

Obtaining a first frequency offset estimation value f ₀ ^u (ka _Rx ) of a current subframe of the receiving antenna ka _Rx according to the following formula:

As an implementation manner, the method further includes:

Smoothing the first frequency offset estimation value f ₀ ^u (ka _Rx ) of the current subframe of the receiving antenna ka _{Rx to} obtain a first frequency offset estimation value f ₁ ^{(u) of the} smoothed current subframe (ka ⁾ _Rx ).

In an embodiment, the pilot sequence included in the received current subframe determines a phase difference of adjacent pilot positions, and is within a range defined by an initial frequency offset value corresponding to the first frequency offset estimation value, Obtaining a dual pilot frequency offset estimation value according to the phase difference, including:

Two pilot channel estimates obtained from two pilot sequences included in the current subframe of the receive antenna ka _Rx

with

And obtaining the phase difference between the two pilot positions of the receiving antenna ka _Rx according to the following formula

Where * indicates the conjugate operator and angle() indicates the angle operator;

Time interval Δt through the two pilot sequences and phase difference between the two pilot sequences

Obtain the double pilot frequency offset estimation result Δf ₂ ^(u) (ka _Rx ) of the receiving antenna ka _Rx according to the following equation:

The initial frequency offset value

Within the limited range, the double pilot frequency offset estimation value ΔΔf ₂ (ka _Rx ) of the receiving antenna ka _Rx is obtained according to the dual pilot frequency offset estimation result Δf ₂ ^(u) (ka _Rx ) and the following equation:

Where T is the maximum range value of the dual pilot frequency offset estimation value; l is a preset integer used to limit the dual pilot frequency offset estimation value to a predetermined range.

As an implementation manner, the initial frequency offset value corresponding to the first frequency offset estimation value is After the dual pilot frequency offset estimation value obtains the frequency offset estimation value of the current subframe, the method further includes:

The frequency offset estimation value f ^u (ka _Rx ) of the current subframe is smoothed by filtering to obtain a frequency offset estimation value f ^(u) (ka _Rx ) of the smoothed current subframe.

In a second aspect, an embodiment of the present invention provides a device for estimating a frequency offset, where the device includes: a first acquiring unit, a second acquiring unit, a third obtaining unit, and a fourth acquiring unit, where

The first acquiring unit is configured to perform initial channel estimation by using the received SRS or Preamble code, and obtain a first frequency offset estimation value of the current subframe;

The second acquiring unit is configured to determine a frequency offset interval in which the first frequency offset estimation value is located, and acquire the first frequency according to a correspondence between a preset frequency offset interval and an initial frequency offset value. The initial frequency offset value corresponding to the partial estimated value;

The third acquiring unit is configured to determine a phase difference of the adjacent pilot positions based on the received pilot sequence included in the current subframe, and is defined by an initial frequency offset value corresponding to the first frequency offset estimation value. Within the range, obtaining a dual pilot frequency offset estimation value according to the phase difference;

The fourth acquiring unit is configured to acquire a frequency offset estimation value of the current subframe according to the initial frequency offset value corresponding to the first frequency offset estimation value and the dual pilot frequency offset estimation value.

As an implementation manner, the first acquiring unit is configured to:

And obtaining a time domain sample value w ^u (n, ka _Rx) of the current subframe of the receiving antenna ka _Rx according to the channel estimation value H ^u and the received data ^Yu and combined with the local pilot sequence P ^u and the following formula ):

Ka _Rx represents the receiving antenna index,

Indicates the size of the RB occupied by the UE, * indicates a conjugate operation, and IDFT indicates an inverse Fourier transform;

And acquires the current subframe ka _Rx antenna receives the phase information of the time-domain sample values w ^u (n, ka _Rx) of said receive antenna ka _Rx current frame of the first sub frequency offset estimate f ₀ ^u (ka _Rx ).

As an implementation manner, the first acquiring unit is configured to:

As an implementation manner, the first acquiring unit is further configured to perform smoothing processing on the first frequency offset estimation value f ₀ ^u (ka _Rx ) of the current subframe of the receiving antenna ka _{Rx to} obtain a smooth current current The first frequency offset estimate of the subframe is f ₁ ^(u) (ka _Rx ).

As an implementation manner, the third acquiring unit is configured to:

with

And a time interval Δt through the two pilot sequences and a phase difference between the two pilot sequences

And at the initial frequency offset value

Within the limited range, the double pilot frequency offset estimation value ΔΔf ₂ (ka _Rx ) of the receiving antenna ka _Rx is obtained from the double pilot frequency offset estimation result Δf ₁ ^(u) (ka _Rx ) and the following equation:

As an implementation manner, the fourth acquiring unit is further configured to perform smoothing processing on the frequency offset estimation value f ^u (ka _Rx ) of the current subframe by using a filtering manner to obtain a frequency offset estimation of the smoothed current subframe. The value f ^(u) (ka _Rx ).

A storage medium having stored therein a computer program configured to perform the aforementioned method of frequency offset estimation.

In the embodiment of the present invention, an initial frequency offset value is obtained according to the first frequency offset estimation value determined by the SRS or Preamble code sent by the UE, and the frequency of the current subframe is obtained by combining the dual pilot frequency offset estimation value in the range of the initial frequency offset value. The partial estimation value not only ensures the accuracy of the frequency offset estimation, but also reduces the complexity of the estimation of the large frequency offset.

DRAWINGS

1 is a schematic flowchart of a method for estimating frequency offset according to an embodiment of the present invention;

2 is a schematic structural diagram of an apparatus for frequency offset estimation according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings.

FIG. 1 is a flowchart of a method for estimating a frequency offset according to an embodiment of the present invention. It should be noted that, in order to be able to clearly explain the technical solution of the embodiment of the present invention, in this embodiment, a UE is used. For example, it can be understood that a person skilled in the art can apply an embodiment of a UE as an example to an embodiment of multiple UEs without creative labor. This method can include:

S101: Perform initial channel estimation by using an SRS or Preamble code sent by a user equipment (UE, User Equipment), and obtain a first frequency offset estimation value of a current subframe of the UE.

Exemplarily, step S101 may specifically include:

First, the UE acquires the channel estimation value H ^u and Y ^u receives data by receiving the current subframe SRS sent by the UE or the current sub-frame Preamble code; specific acquisition process are conventional means of achieving skilled in the art , will not repeat them here;

Then, according to the channel estimation value H ^{u of} the UE and the received data ^Yu , combined with the local pilot sequence P ^u and Equation 1, the time domain sample value w ^u of the current subframe of the receiving antenna ka _Rx of the UE is acquired ( n,ka _Rx ):

Where n is the sampling point number, u is the UE, and k is the subcarrier index corresponding to the UE.

Ka _Rx represents the receiving antenna index,

Next, the phase information acquired according to the time-domain sample values w ^u (n, ka _Rx) of said receive antenna ka _Rx UE in the current sub-frame the UE in a first frequency offset estimated ka _Rx antenna receiving a current sub-frame The value f ₀ ^u (ka _Rx ); in detail, in the embodiment, the phase values of the first half and the second half of the time domain sample value w ^u (n, ka _Rx ) of the current subframe may be separately performed. After averaging, obtain the phase difference between the front and back parts

The phase difference between adjacent sampling points in the time domain sample value w ^u (n, ka _Rx ) of the current subframe may also be averaged to obtain

Then, according to Equation 2, the first frequency offset estimation value f ₀ ^u (ka _Rx ) of the current subframe of the UE in the receiving antenna ka _Rx is obtained:

As an implementation manner, the f ₀ ^u (ka _Rx ) obtained by the formula 2 may be smoothed to obtain a first frequency offset estimation value f ₀ ^(u) (ka _Rx ) of the smoothed current subframe; specifically, The first frequency offset estimation value corresponding to the previous subframe of the current subframe may be weighted and summed with f ₀ ^u (ka _Rx ); it may be understood that the closer the time is to the current subframe, the greater the weight; the farther away from the current time Subframes have smaller weights.

In this embodiment, the corresponding first frequency offset estimation value of the previous subframe of the current subframe may be used.

And f ₀ ^u (ka _Rx ) is subjected to weighted summation according to Equation 3 to smooth out f ₀ ^u (ka _Rx ) to obtain a first frequency offset estimated value f ₀ ^{(u) of the} smoothed current subframe (ka _Rx ):

Where p ₁ is a filtering factor and ₀ ≤ p ₁ ≤ 1.

It can be understood that f ₁ ^(u) (ka _Rx ) is only smoother than f ₀ ^u (ka _Rx ), but f ₀ ^u (ka _Rx ) can also be used for subsequent processing, and f ₁ ^(u) (ka _Rx ) for subsequent processing is only a more preferable scheme of the embodiment, so the first frequency offset estimation value used in the subsequent processing may select f ₀ ^u (ka _Rx ) or The f ₁ ^(u) (ka _Rx ) is selected in the embodiment of the present invention.

S102: Determine a frequency offset interval range in which the first frequency offset estimation value is located, and obtain an initial frequency offset value corresponding to the first frequency offset estimation value according to a correspondence between the preset frequency offset interval range and the initial frequency offset value. ;

Exemplarily, the preset correspondence between the preset frequency offset interval range and the initial frequency offset value may be a mapping table of upper and lower limits and initial frequency offset values of a specific frequency offset range interval, as shown in Table 1. Show,

Table 1

It can be seen from Table 1 that the first frequency offset estimation value can be compared with the upper and lower limits of each frequency offset range section in Table 1, and the frequency offset range interval in which the first frequency offset estimation value is located can be determined, and then Correspondingly, an initial frequency offset value corresponding to the first frequency offset estimation value is obtained. In this embodiment, the initial frequency offset value corresponding to the first frequency offset estimation value of the receiving antenna ka _Rx of the UE may be used.

Said.

S103: Determine a phase difference of adjacent pilot positions based on a pilot sequence included in the received current subframe, and obtain, according to the phase difference, within a range defined by an initial frequency offset value corresponding to the first frequency offset estimation value. Dual pilot frequency offset estimate.

As an embodiment, in this embodiment, S103 may specifically include:

First, according to the two pilot channel estimates obtained by the UE in the two pilot sequences included in the current subframe of the receiving antenna ka _Rx

with

Obtaining the phase difference between the two pilot positions of the UE at the receiving antenna ka _Rx according to Equation 3

Where * indicates the conjugate operator and angle() indicates the angle operator.

Then, the time interval Δt of the two pilot sequences and the phase difference of the two pilot sequences

Obtaining the dual pilot frequency offset estimation result Δf ₁ ^(u) (ka _Rx ) of the UE at the receiving antenna ka _Rx according to Equation 4:

Then, at the initial frequency offset value

Within the limited range, the double pilot frequency offset estimation value ΔΔf ₂ (ka _Rx ) of the UE at the receiving antenna ka _Rx is obtained according to the dual pilot frequency offset estimation result Δf ₂ ^(u) (ka _Rx ) and Equation 5:

S104: Obtain a frequency offset estimation value of the current subframe according to the initial frequency offset value corresponding to the first frequency offset estimation value and the dual pilot frequency offset estimation value.

Exemplarily, in this embodiment, the initial frequency offset value may be

Guiding the double frequency bias estimate ΔΔf ₂ (ka _Rx) adding UE acquires the estimation value f ^u (ka _Rx) offset in the current subframe of the receiving antenna ka _Rx.

As an implementation manner, after acquiring the frequency offset estimation value f ^u (ka _Rx ) of the current subframe of the receiving antenna ka _Rx , the UE may perform smoothing processing on the f ^u (ka _Rx ) by filtering, Obtaining a frequency offset estimation value f ^(u) (ka _Rx ) of the smoothed current subframe;

As an implementation manner, in this embodiment, the frequency offset estimation value of the previous subframe of the receiving antenna ka _Rx may be adopted by the UE.

And f ^u (ka _Rx) according to a weighted sum of the embodiment of formula 6 to obtain the current sub-frame, the smoothed frequency offset estimate ^{_{f (u) (ka Rx)}} :

Where p ₂ is a filter factor and 0 ≤ p ₂ ≤ 1.

The foregoing solution is a method for estimating a frequency offset according to an embodiment of the present invention, where an initial frequency offset value is obtained according to a first frequency offset estimation value determined according to an SRS or a Preamble code sent by a UE, and is within a range of an initial frequency offset value. Combining the dual pilot frequency offset estimation value to obtain the frequency offset estimation value of the current subframe not only ensures the frequency offset estimation accuracy, but also reduces the complexity of the large frequency offset estimation.

Based on the same technical concept of the embodiment shown in FIG. 1, referring to FIG. 2, an apparatus 20 for frequency offset estimation according to an embodiment of the present invention is shown. The apparatus 20 may include: a first acquiring unit 201, and a second acquiring. The unit 202, the third obtaining unit 203, and the fourth obtaining unit 204, wherein

The first acquiring unit 201 is configured to perform initial channel estimation by receiving an SRS or a Preamble code sent by the UE, and acquire a first frequency offset estimation value of the current subframe of the UE;

The second obtaining unit 202 is configured to determine a frequency range in which the first frequency offset estimation value is located, and according to the frequency range and a preset correspondence between the frequency range and an initial frequency offset value, Obtaining an initial frequency offset value corresponding to the first frequency offset estimation value;

The third acquiring unit 203 is configured to calculate a phase difference between two pilot positions based on the received two pilot sequences included in the current subframe of the UE, and within a range defined by the initial frequency offset value, according to The phase difference acquires a dual pilot frequency offset estimation value;

The fourth obtaining unit 204 is configured to acquire a frequency offset estimation value of the current subframe according to the initial frequency offset value and the dual pilot frequency offset estimation value.

Exemplarily, the first obtaining unit 201 is configured to:

The UE acquires by receiving a current sub-frame SRS sent by the UE or the current subframe Preamble code channel estimation value H ^u and receiving data Y ^u;

And obtaining, according to the channel estimation value H ^{u of} the UE and the received data ^Yu , and combining the local pilot sequence ^Pu and the following formula to obtain a time domain sample value w ^u of the current subframe of the receiving antenna ka _Rx ( n,ka _Rx ):

Ka _Rx represents the receiving antenna index,

And a frequency offset estimate value of the UE obtaining a first receive antenna ka _Rx of the current subframe based on the phase information value domain sample w ^u (n, ka _Rx) of said receive antenna ka _Rx UE in the current sub-frame f ₀ ^u (ka _Rx ).

As an implementation manner, the first acquiring unit 201 is configured to:

Obtaining a first frequency offset estimation value f ₀ ^u (ka _Rx ) of the current subframe of the UE in the receiving antenna ka _Rx according to the following formula:

As an implementation manner, the first acquiring unit 201 is further configured to perform smoothing processing on the first frequency offset estimation value f ₀ ^u (ka _Rx ) of the current subframe of the receiving antenna ka _Rx by the UE, to obtain smoothing. The first frequency offset estimation value f ₁ ^(u) (ka _Rx ) of the current current subframe; specifically, the first acquiring unit 201 may estimate the first frequency offset corresponding to the previous subframe of the current subframe f ₀ ^u (ka _Rx ) performs weighted summation; it can be understood that the closer the time is to the current subframe, the larger the weight; the farther away from the current subframe, the smaller the weight.

In this embodiment, the first acquiring unit 201 may be configured according to a corresponding first frequency offset estimation value of a previous subframe of the current subframe.

And f ₀ ^u (ka _Rx ) is subjected to weighted summation according to the following equation to smooth out f ₀ ^u (ka _Rx ) to obtain a first frequency offset estimated value f ₁ ^{(u) of the} smoothed current subframe (ka _{Rx )} ):

Where p ₁ is a filtering factor and ₀ ≤ p ₁ ≤ 1.

It can be understood that f ₁ ^(u) (ka _Rx ) is only smoother than f ₀ ^u (ka _Rx ), but f ₀ ^u (ka _Rx ) can also be used for subsequent module processing, and f ₁ ^{(u )} (ka ^_Rx) module for subsequent processing is merely a more preferred embodiment according to the present embodiment, therefore, a first frequency offset estimation value in the subsequent process modules may be used to select f ₀ ^u (ka _Rx) For example, f ₁ ^(u) (ka _Rx ) may be selected, which is not specifically limited in the embodiment of the present invention.

Exemplarily, the correspondence between the preset frequency range and the initial frequency offset value may be a mapping table of upper and lower limits and initial frequency offset values of a specific frequency range interval, as shown in Table 1.

As an embodiment, as shown in Table 1, the second obtaining unit 202 may be configured to compare the first frequency offset estimation value with the upper and lower limits of each frequency range interval in Table 1, and determine the first frequency offset estimation. The frequency range interval in which the value is located, and then the initial frequency offset value corresponding to the first frequency offset estimation value may also be acquired accordingly. In this embodiment, the initial frequency offset value corresponding to the first frequency offset estimation value of the receiving antenna ka _Rx of the UE may be used.

Said.

Exemplarily, the third obtaining unit 203 is configured to:

Two pilot channel estimation values obtained by the UE according to two pilot sequences included in the current subframe of the receiving antenna ka _Rx

with

Obtaining the phase difference between the two pilot positions of the UE at the receiving antenna ka _Rx according to the following formula

Obtaining the dual pilot frequency offset estimation result Δf ₂ ^(u) (ka _Rx ) of the UE at the receiving antenna ka _Rx according to the following formula:

And obtaining, within the range defined by the initial frequency offset value, the dual pilot frequency offset estimation value ΔΔf of the UE at the receiving antenna ka _Rx according to the dual pilot frequency offset estimation result Δf ₂ ^(u) (ka _Rx ) and the following formula ₂ (ka _Rx ):

As an implementation manner, in this embodiment, the fourth obtaining unit 204 may pass the initial frequency offset value.

Guiding the double frequency bias estimate ΔΔf ₂ (ka _Rx) acquired by adding the offset current subframe UE receiving antenna ka _Rx estimate f ^u (ka _Rx).

As an implementation manner, after acquiring the frequency offset estimation value f ^u (ka _Rx ) of the current subframe of the UE receiving antenna ka _Rx , the fourth acquiring unit 204 is further configured to use the frequency of the current subframe. The partial estimated value f ^u (ka _Rx ) is smoothed by filtering to obtain a frequency offset estimated value f ^(u) (ka _Rx ) of the smoothed current subframe.

As an implementation manner, in this embodiment, the fourth acquiring unit 204 may receive the frequency offset estimation value of the previous subframe of the antenna ka _Rx by using the UE.

The frequency offset estimation value f ^(u) (ka _Rx ) of the smoothed current subframe is obtained by performing weighted summation with f ^u (ka _Rx ) according to the following equation:

Where p ₂ is a filter factor and 0 ≤ p ₂ ≤ 1.

The embodiment provides a frequency offset estimation apparatus 20, which obtains an initial frequency offset value by using a first frequency offset estimation value determined according to an SRS or a Preamble code sent by the UE, and combines the double pilot in a range of the initial frequency offset value. The frequency offset estimation value obtains the frequency offset estimation value of the current subframe, which not only ensures the accuracy of the frequency offset estimation, but also reduces the complexity of the estimation of the large frequency offset.

Embodiments of the present invention also describe a storage medium in which a computer program is stored, the computer program being configured to perform the method of frequency offset estimation of the foregoing embodiments.

Those skilled in the art will appreciate that embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention can take the form of a hardware embodiment, a software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) including computer usable program code.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Realize A means of function specified in a flow or a flow and/or a block diagram of a block or blocks.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Industrial applicability

The present invention obtains an initial frequency offset value by using a first frequency offset estimation value determined according to an SRS or a Preamble code sent by the UE, and obtains a frequency offset estimation of the current subframe by combining the dual pilot frequency offset estimation value in a range of the initial frequency offset value. The value not only ensures the accuracy of the frequency offset estimation, but also reduces the complexity of the estimation of the large frequency offset.

Claims

A method of frequency offset estimation includes:

Performing initial channel estimation by using the received sounding reference signal SRS or Preamble code, and acquiring a first frequency offset estimation value of the current subframe;

Determining a frequency offset interval in which the first frequency offset estimation value is located, and acquiring an initial frequency offset value corresponding to the first frequency offset estimation value according to a correspondence between a preset frequency offset interval and an initial frequency offset value ;

Determining a phase difference of adjacent pilot positions based on a pilot sequence included in the received current subframe, and acquiring a dual derivative according to the phase difference within a range defined by the initial frequency offset value corresponding to the first frequency offset estimation value Frequently biased estimate;

Obtaining a frequency offset estimation value of the current subframe according to the initial frequency offset value corresponding to the first frequency offset estimation value and the dual pilot frequency offset estimation value.
The method according to claim 1, wherein the initial channel estimation by using the received SRS or Preamble code to obtain the first frequency offset estimation value of the current subframe includes:

Acquiring channel estimation value H u and Y u receive data by receiving a current sub-frame of SRS code or the current sub-frame Preamble;

Obtaining the time domain sample value w u (n, ka Rx ) of the current subframe of the receiving antenna ka Rx according to the channel estimation value H u and the received data Yu and combined with the local pilot sequence Pu and the following formula:

w u (n,ka Rx )=IDFT(Y u (k,ka Rx )×H u* (k,ka Rx ))×(IDFT(P u (k))) *

Wherein, n represents a sampling point sequence number, u represents a user equipment UE corresponding to the current subframe, and k represents a subcarrier index corresponding to the UE,
Ka Rx represents the receiving antenna index,
Indicates the size of the resource block RB occupied by the UE, * indicates a conjugate operation, and IDFT indicates an inverse Fourier transform;

Get current subframe ka Rx antenna receives the phase information of the time-domain sample values w u (n, ka Rx) of said receive antenna ka Rx current frame of the first sub frequency offset estimation value
The method according to claim 2, wherein the sampling phase information value w u (n, ka Rx) of the receiving antenna ka Rx acquiring a current time-domain subframe of the receiving antenna ka Rx current sub-frame First frequency offset estimate
include:

Obtaining the phase difference between the first half and the second half of the time domain sample value w u (n, ka Rx ) of the current subframe, respectively, and obtaining the phase difference between the front and back portions

Obtaining a first frequency offset estimate of a current subframe of the receive antenna ka Rx according to the following formula
The method of claim 2, wherein the method further comprises:

First frequency offset estimate for the current subframe of the receive antenna ka Rx
Performing a smoothing process to obtain a first frequency offset estimate of the smoothed current subframe
The method according to claim 1, wherein said determining, based on a received pilot sequence of a current subframe, a phase difference of adjacent pilot positions, and an initial frequency offset value corresponding to said first frequency offset estimation value Within the limited range, the dual pilot frequency offset estimation value is obtained according to the phase difference, including:

Two pilot channel estimates obtained from two pilot sequences included in the current subframe of the receive antenna ka Rx
with
And obtaining the phase difference between the two pilot positions of the receiving antenna ka Rx according to the following formula

Where * indicates the conjugate operator and angle() indicates the angle operator;

Time interval Δt through the two pilot sequences and phase difference between the two pilot sequences
Obtain the dual pilot frequency offset estimation result of the receiving antenna ka Rx according to the following formula

The initial frequency offset value
Estimated results based on the dual pilot frequency offset within a defined range
And obtaining the dual pilot frequency offset estimation value ΔΔf 2 (ka Rx ) of the receiving antenna ka Rx as follows:

Where T is the maximum range value of the dual pilot frequency offset estimation value; l is a preset integer used to limit the dual pilot frequency offset estimation value to a predetermined range.
The method according to claim 1, wherein after acquiring the frequency offset estimation value of the current subframe according to the initial frequency offset value corresponding to the first frequency offset estimation value and the dual pilot frequency offset estimation value, the method Also includes:

The frequency offset estimation value f u (ka Rx ) of the current subframe is smoothed by filtering to obtain a frequency offset estimation value f (u) (ka Rx ) of the smoothed current subframe.
An apparatus for estimating a frequency offset, comprising: a first acquiring unit, a second acquiring unit, a third obtaining unit, and a fourth acquiring unit, where

The first acquiring unit is configured to perform initial channel estimation by using the received sounding reference signal SRS or Preamble code, and obtain a first frequency offset estimation value of the current subframe;

The second acquiring unit is configured to determine a frequency offset interval in which the first frequency offset estimation value is located, and acquire the first frequency according to a correspondence between a preset frequency offset interval and an initial frequency offset value. The initial frequency offset value corresponding to the partial estimated value;

The third acquiring unit is configured to determine a phase difference of the adjacent pilot positions based on the received pilot sequence included in the current subframe, and is defined by an initial frequency offset value corresponding to the first frequency offset estimation value. Within the range, obtaining a dual pilot frequency offset estimation value according to the phase difference;

The fourth acquiring unit is configured to acquire a frequency offset estimation value of the current subframe according to the initial frequency offset value corresponding to the first frequency offset estimation value and the dual pilot frequency offset estimation value.
The device according to claim 7, wherein the first obtaining unit is configured to:

Acquiring channel estimation value H u and Y u receive data by receiving a current sub-frame of SRS code or the current sub-frame Preamble;

And obtaining a time domain sample value w u (n, ka Rx) of the current subframe of the receiving antenna ka Rx according to the channel estimation value H u and the received data Yu and combined with the local pilot sequence P u and the following formula ):

w u (n,ka Rx )=IDFT(Y u (k,ka Rx )×H u* (k,ka Rx ))×(IDFT(P u (k))) *

Wherein, n represents a sampling point sequence number, u represents a user equipment UE corresponding to the current subframe, and k represents a subcarrier index corresponding to the UE,
Ka Rx represents the receiving antenna index,
Indicates the size of the resource block RB occupied by the UE, * indicates a conjugate operation, and IDFT indicates an inverse Fourier transform;

And acquires the current subframe ka Rx antenna receives the phase information of the time-domain sample values w u (n, ka Rx) of said receive antenna ka Rx current frame of the first sub frequency offset estimate f 0 u (ka Rx ).
The device according to claim 8, wherein the first obtaining unit is configured to:

Obtaining the phase difference between the first half and the second half of the time domain sample value w u (n, ka Rx ) of the current subframe, respectively, and obtaining the phase difference between the front and back portions

Obtaining a first frequency offset estimate of a current subframe of the receive antenna ka Rx according to the following formula
The apparatus according to claim 8, wherein the first obtaining unit is further configured to estimate a first frequency offset of a current subframe of the receiving antenna ka Rx
Smoothing is performed to obtain a first frequency offset estimated value f 1 (u) (ka Rx ) of the smoothed current subframe.
The device according to claim 7, wherein the third obtaining unit is configured to:

Two pilot channel estimates obtained from two pilot sequences included in the current subframe of the receive antenna ka Rx
with
And obtaining the phase difference between the two pilot positions of the receiving antenna ka Rx according to the following formula

Where * indicates the conjugate operator and angle() indicates the angle operator;

And a time interval Δt through the two pilot sequences and a phase difference between the two pilot sequences
Obtain the dual pilot frequency offset estimation result of the receiving antenna ka Rx according to the following formula

And at the initial frequency offset value
Within the defined range, based on the results of the dual pilot frequency offset estimation
And obtaining the dual pilot frequency offset estimation value ΔΔf 2 (ka Rx ) of the receiving antenna ka Rx as follows:

Where T is the maximum range value of the dual pilot frequency offset estimation value; l is a preset integer used to limit the dual pilot frequency offset estimation value to a predetermined range.
The apparatus according to claim 7, wherein the fourth acquiring unit is further configured to perform smoothing processing on the frequency offset estimation value f u (ka Rx ) of the current subframe by using a filtering manner to obtain a smooth current sub-sub The frequency offset estimate of the frame is f (u) (ka Rx ).
A storage medium storing a computer program configured to perform the method of frequency offset estimation according to any one of claims 1 to 6.